Kinetics and Energy Assessment of Potential Biofuels and Additives Derived from Fructose via Acid Alcoholysis: 5-Alkoxymethyl Furfural and Alkyl Levulinates

Bioderived platform molecules such as alkyl levulinates (RLs) and 5-alkoxymethyl furfurals (RMFs) show significant promise as renewable biofuels and fuel additives. However, the influence of the alkyl chain length on their higher heating value (HHV) and production kinetics remains underexplored. This study investigates the acid-catalyzed solvolysis of fructose in six linear alcohols (MeOH to HeOH) and evaluates the formation of RL and RMF products. The roles of three commercial acid catalysts (Amberlyst 15 H+, Amberlite IR120 H+, and Y-zeolite H+) and the polar aprotic cosolvent γ-valerolactone (GVL) are compared. Our results show that 5-(Methoxymethyl)furfural (MMF) is highly unstable under reaction conditions, leading to its rapid conversion to methyl levulinate (ML); therefore, targeting ML over MMF is more practical when using methanol. For other alcohols, RMFs are preferred over RLs due to their higher volumetric energy density, improved thermal stability, and enhanced blending properties in fuel applications. Heating value measurements and kinetic analyses reveal that longer alkyl chains enhance the higher heating value (HHV) of both alkyl levulinates (RLs) and 5-alkoxymethyl furfurals (RMFs), although an increased chain length may reduce reaction rates.